1. Field of the Invention
This invention relates generally to the field of fork lift attachments to convert a multi-purpose bucket of a loader into a fork lift and more particularly to the field of doing so in a removable manner that is easy to install and does not damage the bucket.
2. Discussion of the Background
In the construction and agriculture industries loaders are often used as multi-functional pieces of equipment. Some of these loaders make use of a multi-purpose bucket in order to be more versatile and have one piece of equipment able to perform many tasks. These multi-purpose buckets are also referred to as 4-in-1 buckets or clam shell buckets. The bucket has two jaws that are pivotally mounted to each other with their positions relative to each other being controlled by hydraulic cylinders. The bucket is then otherwise operated and moved as any regular bucket would be on a loader.
There have been fork lift attachments for regular buckets, such as U.S. Pat. No. 6,022,184 to Friedland, wherein the attachments allow for the temporary conversion of a regular bucket to perform fork lift jobs. This conversion ability is very advantageous in that it allows a single piece of equipment to be used for different functions without a major investment in separate specialized equipment.
For multi-purpose buckets, prior fork lift attachments have relied upon cumbersome and sometimes unsecured means of attachment. Examples are illustrated by U.S. Pat. No. 3,667,633 to Cappella and U.S. Pat. Nos. 6,287,070, 6,527,497 and 6,547,508 to Perry. These designs have serious drawbacks. In practice the tips of the fork lift tine often are pushed upward, intentionally or unintentionally, creating forces that may dislodge the fork lift attachments. The result may be an insecure fork lift or dropped or damaged cargo which may cause personal injury or property damage. Inadvertent dropping of the fork lift attachment from the bucket can also occur if the jaws of the multi-purpose bucket open, even if only partially.
A second shortcoming of these prior designs is the components that are used. Some, such as in the Perry design, have large steel plates that must be placed in the bucket with attached T or I beams. These can weigh a significant amount, thus reducing the useable payload weight. In addition the large, heavy components necessarily cannot be easily installed by an individual and can pose difficulties in field installations. Further, the Perry design has an expensively fabricated tine component which is necessary in order to have the front of the tines be at ground level. The fabrication to obtain such a configuration while maintaining strength is very expensive and involved.
Another shortcoming of some designs is the use of semi-permanent bolts or other fasteners to secure the fork lift attachments to the bucket. Placement of holes or other similar permanent alterations to the bucket are not advisable, as it diminishes the integrity of the bucket and can initiate degradation or shortening of the life of the bucket. If the machine is a rental or loaned piece of equipment, such alterations are normally not permitted.